Investments Investments (Repurchase Agreements and Securities Lending) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	$ 7,529	$ 11,063
Overnight and Continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	7,529	11,063
Up 30 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	0	0
30 days or greater
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	0	0
U.S. Treasury securities and obligations of U.S. government authorities and agencies
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	0	8,169
U.S. Treasury securities and obligations of U.S. government authorities and agencies | Overnight and Continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	0	8,169
U.S. Treasury securities and obligations of U.S. government authorities and agencies | Up 30 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	0	0
U.S. public corporate securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	5,048	628
U.S. public corporate securities | Overnight and Continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	5,048	628
U.S. public corporate securities | Up 30 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	0	0
Foreign public corporate securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	2,481	2,266
Foreign public corporate securities | Overnight and Continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	2,481	2,266
Foreign public corporate securities | Up 30 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Total Cash collateral for loaned securities	$ 0	$ 0